/*******************************************************************************

        @file Primes.d

        Copyright (C) 2004 Kris Bell

        This software is provided 'as-is', without any express or implied
        warranty. In no event will the authors be held liable for damages
        of any kind arising from the use of this software.

        Permission is hereby granted to anyone to use this software for any
        purpose, including commercial applications, and to alter it and/or
        redistribute it freely, subject to the following restrictions:

        1. The origin of this software must not be misrepresented; you must
           not claim that you wrote the original software. If you use this
           software in a product, an acknowledgment within documentation of
           said product would be appreciated but is not required.

        2. Altered source versions must be plainly marked as such, and must
           not be misrepresented as being the original software.

        3. This notice may not be removed or altered from any distribution
           of the source.


                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


        @version        Initial version, April 2004
        @author         Kris


*******************************************************************************/

// originally: module primes;
module imports.inline2a;

class Primes
{
        private
         static const short[] primes =
        [
           2,    3,    5,    7,   11,   13,   17,   19,   23,   29,
          31,   37,   41,   43,   47,   53,   59,   61,   67,   71,
          73,   79,   83,   89,   97,  101,  103,  107,  109,  113,
         127,  131,  137,  139,  149,  151,  157,  163,  167,  173,
         179,  181,  191,  193,  197,  199,  211,  223,  227,  229,
         233,  239,  241,  251,  257,  263,  269,  271,  277,  281,
         283,  293,  307,  311,  313,  317,  331,  337,  347,  349,
         353,  359,  367,  373,  379,  383,  389,  397,  401,  409,
         419,  421,  431,  433,  439,  443,  449,  457,  461,  463,
         467,  479,  487,  491,  499,  503,  509,  521,  523,  541,
         547,  557,  563,  569,  571,  577,  587,  593,  599,  601,
         607,  613,  617,  619,  631,  641,  643,  647,  653,  659,
         661,  673,  677,  683,  691,  701,  709,  719,  727,  733,
         739,  743,  751,  757,  761,  769,  773,  787,  797,  809,
         811,  821,  823,  827,  829,  839,  853,  857,  859,  863,
         877,  881,  883,  887,  907,  911,  919,  929,  937,  941,
         947,  953,  967,  971,  977,  983,  991,  997, 1009, 1013,
        1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069,
        1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151,
        1153, 1163, 1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223,
        1229, 1231, 1237, 1249, 1259, 1277, 1279, 1283, 1289, 1291,
        1297, 1301, 1303, 1307, 1319, 1321, 1327, 1361, 1367, 1373,
        1381, 1399, 1409, 1423, 1427, 1429, 1433, 1439, 1447, 1451,
        1453, 1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511,
        1523, 1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583,
        1597, 1601, 1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657,
        1663, 1667, 1669, 1693, 1697, 1699, 1709, 1721, 1723, 1733,
        1741, 1747, 1753, 1759, 1777, 1783, 1787, 1789, 1801, 1811,
        1823, 1831, 1847, 1861, 1867, 1871, 1873, 1877, 1879, 1889,
        1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987,
        1993, 1997, 1999, 2003, 2011, 2017, 2027, 2029, 2039, 2053,
        2063, 2069, 2081, 2083, 2087, 2089, 2099, 2111, 2113, 2129,
        2131, 2137, 2141, 2143, 2153, 2161, 2179, 2203, 2207, 2213,
        2221, 2237, 2239, 2243, 2251, 2267, 2269, 2273, 2281, 2287,
        2293, 2297, 2309, 2311, 2333, 2339, 2341, 2347, 2351, 2357,
        2371, 2377, 2381, 2383, 2389, 2393, 2399, 2411, 2417, 2423,
        2437, 2441, 2447, 2459, 2467, 2473, 2477, 2503, 2521, 2531,
        2539, 2543, 2549, 2551, 2557, 2579, 2591, 2593, 2609, 2617,
        2621, 2633, 2647, 2657, 2659, 2663, 2671, 2677, 2683, 2687,
        2689, 2693, 2699, 2707, 2711, 2713, 2719, 2729, 2731, 2741,
        2749, 2753, 2767, 2777, 2789, 2791, 2797, 2801, 2803, 2819,
        2833, 2837, 2843, 2851, 2857, 2861, 2879, 2887, 2897, 2903,
        2909, 2917, 2927, 2939, 2953, 2957, 2963, 2969, 2971, 2999,
        3001, 3011, 3019, 3023, 3037, 3041, 3049, 3061, 3067, 3079,
        3083, 3089, 3109, 3119, 3121, 3137, 3163, 3167, 3169, 3181,
        3187, 3191, 3203, 3209, 3217, 3221, 3229, 3251, 3253, 3257,
        3259, 3271, 3299, 3301, 3307, 3313, 3319, 3323, 3329, 3331,
        3343, 3347, 3359, 3361, 3371, 3373, 3389, 3391, 3407, 3413,
        3433, 3449, 3457, 3461, 3463, 3467, 3469, 3491, 3499, 3511,
        3517, 3527, 3529, 3533, 3539, 3541, 3547, 3557, 3559, 3571,
        3581, 3583, 3593, 3607, 3613, 3617, 3623, 3631, 3637, 3643,
        3659, 3671, 3673, 3677, 3691, 3697, 3701, 3709, 3719, 3727,
        3733, 3739, 3761, 3767, 3769, 3779, 3793, 3797, 3803, 3821,
        3823, 3833, 3847, 3851, 3853, 3863, 3877, 3881, 3889, 3907,
        3911, 3917, 3919, 3923, 3929, 3931, 3943, 3947, 3967, 3989,
        4001, 4003, 4007, 4013, 4019, 4021, 4027, 4049, 4051, 4057,
        4073, 4079, 4091, 4093, 4099, 4111, 4127, 4129, 4133, 4139,
        4153, 4157, 4159, 4177, 4201, 4211, 4217, 4219, 4229, 4231,
        4241, 4243, 4253, 4259, 4261, 4271, 4273, 4283, 4289, 4297,
        4327, 4337, 4339, 4349, 4357, 4363, 4373, 4391, 4397, 4409,
        4421, 4423, 4441, 4447, 4451, 4457, 4463, 4481, 4483, 4493,
        4507, 4513, 4517, 4519, 4523, 4547, 4549, 4561, 4567, 4583,
        4591, 4597, 4603, 4621, 4637, 4639, 4643, 4649, 4651, 4657,
        4663, 4673, 4679, 4691, 4703, 4721, 4723, 4729, 4733, 4751,
        4759, 4783, 4787, 4789, 4793, 4799, 4801, 4813, 4817, 4831,
        4861, 4871, 4877, 4889, 4903, 4909, 4919, 4931, 4933, 4937,
        4943, 4951, 4957, 4967, 4969, 4973, 4987, 4993, 4999, 5003,
        5009, 5011, 5021, 5023, 5039, 5051, 5059, 5077, 5081, 5087,
        5099, 5101, 5107, 5113, 5119, 5147, 5153, 5167, 5171, 5179,
        5189, 5197, 5209, 5227, 5231, 5233, 5237, 5261, 5273, 5279,
        5281, 5297, 5303, 5309, 5323, 5333, 5347, 5351, 5381, 5387,
        5393, 5399, 5407, 5413, 5417, 5419, 5431, 5437, 5441, 5443,
        5449, 5471, 5477, 5479, 5483, 5501, 5503, 5507, 5519, 5521,
        5527, 5531, 5557, 5563, 5569, 5573, 5581, 5591, 5623, 5639,
        5641, 5647, 5651, 5653, 5657, 5659, 5669, 5683, 5689, 5693,
        5701, 5711, 5717, 5737, 5741, 5743, 5749, 5779, 5783, 5791,
        5801, 5807, 5813, 5821, 5827, 5839, 5843, 5849, 5851, 5857,
        5861, 5867, 5869, 5879, 5881, 5897, 5903, 5923, 5927, 5939,
        5953, 5981, 5987, 6007, 6011, 6029, 6037, 6043, 6047, 6053,
        6067, 6073, 6079, 6089, 6091, 6101, 6113, 6121, 6131, 6133,
        6143, 6151, 6163, 6173, 6197, 6199, 6203, 6211, 6217, 6221,
        6229, 6247, 6257, 6263, 6269, 6271, 6277, 6287, 6299, 6301,
        6311, 6317, 6323, 6329, 6337, 6343, 6353, 6359, 6361, 6367,
        6373, 6379, 6389, 6397, 6421, 6427, 6449, 6451, 6469, 6473,
        6481, 6491, 6521, 6529, 6547, 6551, 6553, 6563, 6569, 6571,
        6577, 6581, 6599, 6607, 6619, 6637, 6653, 6659, 6661, 6673,
        6679, 6689, 6691, 6701, 6703, 6709, 6719, 6733, 6737, 6761,
        6763, 6779, 6781, 6791, 6793, 6803, 6823, 6827, 6829, 6833,
        6841, 6857, 6863, 6869, 6871, 6883, 6899, 6907, 6911, 6917,
        6947, 6949, 6959, 6961, 6967, 6971, 6977, 6983, 6991, 6997,
        7001, 7013, 7019, 7027, 7039, 7043, 7057, 7069, 7079, 7103,
        7109, 7121, 7127, 7129, 7151, 7159, 7177, 7187, 7193, 7207,
        7211, 7213, 7219, 7229, 7237, 7243, 7247, 7253, 7283, 7297,
        7307, 7309, 7321, 7331, 7333, 7349, 7351, 7369, 7393, 7411,
        7417, 7433, 7451, 7457, 7459, 7477, 7481, 7487, 7489, 7499,
        7507, 7517, 7523, 7529, 7537, 7541, 7547, 7549, 7559, 7561,
        7573, 7577, 7583, 7589, 7591, 7603, 7607, 7621, 7639, 7643,
        7649, 7669, 7673, 7681, 7687, 7691, 7699, 7703, 7717, 7723,
        7727, 7741, 7753, 7757, 7759, 7789, 7793, 7817, 7823, 7829,
        7841, 7853, 7867, 7873, 7877, 7879, 7883, 7901, 7907, 7919
        ];

        /*********************************************************************

                Binary-chop search on sorted data.

        *********************************************************************/

        private static ptrdiff_t bsearch (in short[] array, short match)
        {
                ptrdiff_t l, u, m;

                l = -1;
                u = array.length;

                while (l+1 != u)
                      {
                      m = (l + u) / 2;
                      if (array[m] < match)
                          l = m;
                      else
                         u = m;
                      }

               if (u >= array.length || array[u] != match)
                   return -u;
               return u;
        }

        /**********************************************************************

                return a prime number between 2 and 7919 (inclusive) that
                is equal to or larger than the given 'target' number.

        **********************************************************************/

        static int lookup (short target)
        {
                auto index = bsearch (primes, target);
                if (index < 0)
                    index = -index;

                if (index >= primes.length)
                    index = primes.length - 1;

                return primes[index];
        }
}
